|The importance of Limapontia capitata (Mueller) (Opisthobranchia, Sacoglossa) as a primary consumer in the Cladophora-belt|
Jensen, K. (1976). The importance of Limapontia capitata (Mueller) (Opisthobranchia, Sacoglossa) as a primary consumer in the Cladophora-belt, in: Persoone, G. et al. (Ed.) Proceedings of the 10th European Symposium on Marine Biology, Ostend, Belgium, Sept. 17-23, 1975: 2. Population dynamics of marine organisms in relation with nutrient cycling in shallow waters. pp. 339-350
In: Persoone, G.; Jaspers, E. (Ed.) (1976). Proceedings of the 10th European Symposium on Marine Biology, Ostend, Belgium, Sept. 17-23, 1975: 2. Population dynamics of marine organisms in relation with nutrient cycling in shallow waters. IZWO/Universa Press: Wetteren. ISBN 90-6281-002-0. 712 pp., more
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|Document type: Conference paper|
The fluctuations of a Limapontia capitata (Mueller) population in the Cladophora-belt of a jetty at Hellebaek on the north coast of Zealand were recorded monthly during a 3 years period. The population fluctuated from < 100 animals/l of Cladophora spp. in the winter to approximately 3,000 animals/l of Cladophora just after settling. A size-frequency diagram of the population was made for the last summer of the sampling period. By means of this size-frequency diagram and figures from various papers, it was estimated that 1-10% of the total standing crop of Cladophora was eaten by the Limapontia capitata population. Like other sacoglossans, L. capitata feeds by piercing algal cells and sucking out the cell sap. It is stated that L. capitata has to survive the winter as adults, because the eggs are destroyed by temperatures below 1-2 °C. According to various authors, no (or very few) larvae have been found in January and February. A negative geotactic response occurs when L. capitata is kept in darkness, and a faint negative phototaxis could also be observed. It is suggested that the combined effect of these two responses accounts for the maintenance of the animals at the most suitable depth. The starvation tolerance was determined to be 9-10 days (LD50). It may be concluded that an actual lack of food for the Limapontia capitata population is only likely to occur during the autumn, when a large proportion of the algal material is washed away by the autumn storms, while the L. capitata population is still at a high level and new larvae are still settling. Ecologically the most important feature of Limapontia capitata is that these animals are capable of consuming the Cladophora species, which constitute a considerable proportion of the intertidal macroalgae in certain localities.